Columbia PicturesWe're all capable of letting life get to us from time to time. Whether it's the stress of a boring and frustrating job or a tense relationship, life can have a habit of throwing situations our way that can turn us into a nervous wreck. While it's never pleasant when it happens to us, watching someone else going through a breakdown is something you can't help but be fascinated by. Like a guest on Jeremy Kyle or Jerry Springer going nuts on television, we know we shouldn't be entertained and fascinated but we are anyway. For an actor, portraying a convincing breakdown is perhaps the ultimate challenge; a careful balance of fragility transforming into something approaching madness. Here are ten of the most brilliantly realistic movie breakdowns featuring characters who completely crack up as the film progresses; some of the finest performances ever committed to the screen.